Offered to select Facebook partners, the data includes not just
technical information about Facebook members’ devices and use of
Wi-Fi and cellular networks, but also their past locations,
interests, and even their social groups. This data is sourced not
just from the company’s main iOS and Android apps, but from
Instagram and Messenger as well. The data has been used by
Facebook partners to assess their standing against competitors,
including customers lost to and won from them, but also for more
controversial uses like racially targeted ads.

Some experts are particularly alarmed that Facebook has marketed
the use of the information — and appears to have helped directly
facilitate its use, along with other Facebook data — for the
purpose of screening customers on the basis of likely
creditworthiness. Such use could potentially run afoul of federal
law, which tightly governs credit assessments.